American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 57
ent -f*, the currents from both coils will coincide in direction through tliebrushes. The collection of coils and the core compose the armature of the dynamo ma-chine. Iq practice the brushes are jjlaced on the commutator at, or near the point wherethe reversal of polarity in the coils takes place.… … which the armature is caused to revolve rapidly between the poles of the magnet. The magnet used to produce the magnetic field in which the armature rotates, istermed the field magnet. Occasionally, permanent magnets have been used as field magnets, but ordinarily, electro-magnets are employed for…
Telegraph
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